Two renewable energy projects with the capacity to supply more than 235,000 homes are being put on the planning fast track.

Environment Minister Trevor Mallard says he will "call in" Contact Energy's planned Te Mihi geothermal power station near Taupo and Unison Networks' Te Waka windfarm because they are of national significance.

Under special Resource Management Act powers the applications can be referred directly to either a board of inquiry or the Environment Court for decisions, instead of the usual process through district and regional councils.

Mr Mallard said a board would rule on Te Mihi and the court on Unison's Hawkes Bay project, given it had already considered the proposal.

Contact Energy plans to build a 225MW station at Te Mihi as part of a big expansion of geothermal generation over the next five years.

Its chief executive, David Baldwin, said the station was an important step towards New Zealand's goal of having 90 per cent of electricity generated from renewable sources by 2025.

"The Government's intention to call in the resource consent application for this project under the RMA will streamline the process and avoid unnecessary delays, increasing confidence that the plant could be generating electricity by 2011.

"At the end of the day the project will be judged on its merits, like any other resource consent application, but without the potential for lengthy appeals dragging the process out for a number of years," said Mr Baldwin.

Te Mihi geothermal power station will provide enough electricity to power more than 200,000 homes a year.

The re-consenting of Contact's Wairakei and Clutha River/Mataau hydro operations this year took well over six years from beginning to end. "New Zealand cannot afford to allow this to happen with large new renewable electricity generation projects."

Contact was likely to seek call-in of the company's resource consent applications for a similar sized geothermal power station at Tauhara in Taupo in the second half of next year.

Unison's 34 wind-turbine Te Waka site had resource consent turned down by the Environment Court in April after initially being approved by the Hastings District Council.

The wind farm at the southern end of the Te Waka ranges could generate about 102MW. The call-in notices would be issued next month.

In August Transpower's upper North Island transmission project was called in after concern that delays could affect the integrity of the grid.